Power unit



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how www @NN SN s Rop, .Vm o/ Mw .fum LWU NTE@ WMA QN NBOYm UHR QN Patented Sept. 21, 1948 Delbert L. Lotta, Kent, Ohio, and'lloy 'l'. Buey and Harold E. Waldron, Detroit, Mich., assignors to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Application November 2, 1942. Serial No. 464,182

(Cl. 'i4-114) 1 Claim.

This invention relates to improvements in constant speed transmission mechanisms of the intermittent uni-directional variable throw crank typt More specifically it relates to an improved transmission of this type which is simpler. more compact, more economical to build and more durable than those heretofore known.v

The primary object of the invention resides in the provision of a transmission of this type hav`` ing the foregoing characteristics which is particularly suitable for driving an electric generator. l

For some years the advantages of the use of A. C. power on airplanes, vehicles, small boats, etc., has been appreciated.- The fact that vari able speed internal combustion engines usually constitute the driving power source for these vehicles has heretofore prevented the use of A.. C. generative equipment because the frequency of an A. C. vsupply system must be maintained within approximately 5% of normal or undue heating of transformers, relays, etc., results. Furthermore in the case of aircraft, it is necessary to have full electric power available for the operation of auxiliaries such as landing gear, gun

turrets, bomb release mechanism, etc. even when the craft is proceeding at slow speed with the motors throttled down.

Our improved transmission is extremely well adapted for driving an A. C. generator and we have illustrated several embodiments of a complete A. C. power unit adapted for use with an aircraft or'similar engine. It is, howeverl desired to emphasize the fact that the transmission is useful for and adaptable to many other uses.

In the drawings accompanying this description,

Fig. 1 is an elevational sectional view of the transmission.

Fig. 2 is an enlarged section taken along the line 2--2 of Fig. 1.

Fig. 3 is a section taken along the line 3--3 of Fig. 2.

Fig. 4. is an enlarged section taken along the line l-'4 of Fig. 1.

Fig. 5 is an enlarged section taken along the line 5-5 of Fig. 1.

Fig. 6 is an enlarged section taken along th line l--I of Fig. 1.

Fig. 6-A is a perspective detail view of the Fig. 6 mechanism.

Fig. 7 is a perspective view of the transmission mechanism drawn to the same scale as Fig. 1, certain parts being broken away to illustrate details.

Fig. 8 is a schematic wiring diagram of the transmission control system.A

Fig. 9 is a sectional view taken along the line 8-9 of Fig. 11 of the gear carrier.

'Fig'. 10 is a rear elevation of the gear carrier.

Fig. 11'is a front elevation of the gear carrier.

Fig. 12 is an elevational sectional view of an electrical power unit wherein a fluid coupling is used in conjunction with the transmission for driving agenerator, and

Fig. 13 is an elevational section view of a modifled electrical power plant arrangement.

Referring to Figs. 1 to 8 for the present, Il designates the input shaft and Il the output shaft. The two shafts are coaxially mounted in a two-part generally cylindrical casing i2.

Bolts I3 are provided for securing the two parts of the-casing together and the front face of the .casing carries the bolts or studs i4 for mounting the casing on a support, as for example, an internal combustion engine block. The shaft I0 is adapted to engage the accessory drive member (not shown) of the engine, and the shaft il is adapted to engage the driving member 20 of an engine driven auxiliary such as a 8enerator, supercharger, or the like.

An anti-friction bearing i8 journals the shaft I0 in the casing ,and the shaft il is rotatably carried at its rear end by an elongated bushing 2i having an outer enlarged flange secured to the casing by cap screws 2|. shaft il is piloted in the hollow portion 2l of shaft Ill, a needle bearing 2l journalling the two as shown. Lubricant is supplied to the transmission through the passage 22 which is preferably connected to the main engine oil supply.

The passage 22 connects with the oil distribution passages 23, 24, 25' from which the oli flows through the mechanism. Overflow from the front bearing i9 is collected and returned to the sump through chamber' l5 arid passage i6. and a drain passage I8 is provided at the lowest part ofthe casing.

5o The shaft II0 is formed at its rear portion with The front end of an enlarged plate 28 to which is `secured by cap screws 28 a cage 30. 'Ihe cage has a hub 3| which receives and journals the inner portion 32 of the elongated bushing 2|. The cage structure which includes the members 2l and 30 is provided With four axially spaced bearing receiving holes 34 and 35 (see Figs. 9, 10 and 11) in each of which is iournaled by means of antifriction bearings a crank element '33.

Each crank element consists of an enlarged annular portion 36' and an axial reduced annular portion 31. 'Ihe reduced portion 31 carries a pair of integrally formed gears 38, 33 of different pitch diameters, and the portion 36' carries a gear 40. The gears 38. 39 are freely rotatable as a unit on the member 36 and the gear 40 is mounted thereon by means of an overrunning one-way clutch generally designated by the numeral 4|.

The clutch 4| is shown in detail in Figs. 6 and 6-A and comprises a set of cams 42 spaced by rollers 43. The carns extend axially beyond the rollers at each end thereof and are provided at each end with a cut-out portion for receiving a spring member 44. The latter is shaped as illustrated and serves to retain the cams and rollers in assembled relation as well as urge the cams in a counterclockwise direction as seen in Fig. 6 wherein they tend to wedge between the hub 38 and the gear 40 and thereby provide a driving connection therebetween when the crank element 36 rotates clockwise. Counterclockwise rotation of the member 36 will cause a slight clockwise rotation of the cams which releases them from wedging between the hub and gear and permits an overrunning motion between these two members.

In practice four sets of crank elements, over` running clutches and gears 4|I are provided, but it has been found necessary to provide only two sets of the gears 38, 39 which are disposed 180" apart on the cage structure. When only two sets of gears 38, 39 are used, spacers are provided on the reduced portions 31 of the driving members between the bearing for the forward end of the member 36 and the washer 45 which retains the bearings in place.

Each crank element 35 has an integral crank pin 46 on which is rotatably carried a shoe 41.

The shoe has a lip 4B which externally engages a cup-shaped washer 43. The latter prevents the shoes from iiying outwardly under the influence of centrifugal force and acts as a spacer. An arcuate projection 33' formed on the crank element spaces the shoe axially for free swinging relatively thereto. The shoes 41 are provided with internal accurately formed arcuate surfaces which engage a ring 50 carried by an eccentric The eccentric carries an integral worm wheel segment 52 which meshes with a worm 53. Retation of the worm causes corresponding rotation of the eccentric 5| on the eccentrically shaped hub 54 of the bushing 2|.

From the description so far it may be seen that rotation of the shaft I3 and the cage 30 will drag the shoes 41 around the eccentric 5| and if the latter is positioned in neutral or concentric position with 4its center coincident with that of the shaft there will be no oscillation of the crank elements 36 or of the gears 40 although the latter will be clutched to the driving members 3l by thel one-way clutches 4|.

The gears 4|| mesh with a gear 55 formed intemesh with the gears 3l. The gears 55-53 are 4 iournaled on the shaft for free rotation with respect thereto. The inner end of the output shaft is formed with a. gear I1 which meshes with the gears 33, thus it will be seen that when the eccentric 5I is in neutral the entire cage assembly including the gears 33, 33 and 4l revolves with the gears themselves stationary. The gear 51 is therefore turned at the speed of thecage and a one to one ratio exists between the shafts l0 and il.

Adjustment of the eccentric 4| to a position that is eccentric with respect to the shaft will cause the crank elements 33 to be oscillated in succession as the respective shoes 41 pass over thehigh portion of the eccentric. This voscillation is intermittent and the amplitude depends upon the amount of eccentricity of the member 5|. Because of the one-way clutch 4| each oscillation -of a crank element 33 will impart a rotative impulse to the corresponding gear 40 which rotation will be transmitted through gears 55, Il. 39, 3l and 51 to shaft In cases where a constant speed input is available and a variable speed output desired, the overdrive speed of the shaft can, of course, be controlled by adjustment of the eccentric Il.

When the eccentric is in neutral position, the' In the present instance where it is desired to maintain the output shaft at -constant speed within narrow limits, control mechanism is provided for adjusting the eccentric in accordancel with increase or decrease of the speed of the output shaft above or below a predetermined value.

This control mechanism is illustrated in Figs. 2 to 5 and 8. The worm 33 which drives the eccentric adjusting worm wheel 52 is iournaled in the casing i2 as shown in Fig. 4. One end of the worm shank 40 is provided with a slot which receives a key formed on the end of a shaft 3| of a reversible electric motor O2. The motor is mounted on a casing bracket -63 and a threaded fitting 64 is provided for convenience of assembly of the worm and motor shaft.

The motor B2 is energized through three terminals designated 3l, 3i and 31. I'he terminal 4i is connected through a wire Il to s. battery Il which is grounded at 1l to the casing I2 or to the metal frame of the aircraft or other vehicle on which the transmission is mounted. Terminal Si is connected by a wire 1| to a relay operated switch 12 and terminal l1 is likewise connected by wire 13 to a relay operated switch 14. For convenience switches 12 and 14 will be referred to as the "underspeed" and "overspeed switches respectively and the relays 1l and 1l for operating these switches will be called the underspeed relay and the overspeed relay. The underspeed switch 12 connects the motor terminal Il to ground at 11 and the overspeed switch 14 connects the motor terminal 61 to ground at 1I.

'I'he switch operating relays 1l and 13 are connected to the battery Il. through the limity switches indicated diagrammatically at 13, Il, which switches are normally closed but are adapted to be opened by the eccentric l2 in response to its v'rotation to the limit of its moveber 02; the arm 86 is adapted to engage a switch member08 connected to the underspeed relay in response to movement of the member 82 toward the right of Fig. 2, and the arm 05 is adapted to engage a switch member 81 connected to the overspeed relay in response to movement of the member 02 toward the left ofV Fig. 2. The switch 0| may be obtained commercially in a variety of forms and will be described only suiiiciently to make the operation apparent as the details thereof form no part of the present invention.

To-and-fro movement of the switch member 02 is controlled by a speed-responsive operated governor mechanism shown in its entirety in Fig.

2. Both the switch and the governor are enclosed in a housing 90 which is threaded into an elongated boss 9| forming part of the end cover 92 of the main transmission housing. The housing 90 has a bore 93 in which is rotatably carried a member 94 having an enlarged outer end 95 on which are pivoted a pair of weights 96. vThe weights include ears 91 which bear against a member 98. The latter is fixed on a plunger 99 reciprocally carried in the bore |00 of the member 94 by means of a snap ring I 0| which holds the member against a shoulder I 02 on the plunger as shown. A coil spring |03 acts between the with the elongated stem |01 of a worm |08 which is rotatably carried in the boss 9| in driving engagement with a worm wheel |09 splined onl the output shaft II. Rotation of the shaft I| will cause corresponding rotation of the stem |01 and member 94 and the tendency for the weights 95 to swing outwardly will exert force -against the member 98 tending to thrust the plunger 99 toward the left of Fig. 2.

In practice the springs |03 and |04 are selected and adjusted such that the spring I 03 will maintain the switch 3| closed to energize the underspeed relay 15 until the desired speed of the shaft has been reached whereupon the force of the weight-s 96 will thrust the plunger inwardly just sufciently to permit the spring |04 to open the switch. Should the speed of shaft Il rise -above the desired value. the increased centrifugal force acting on the weights 96 will cause further inward movement of the plunger 99 and permit the spring |04 to close the switch and thereby energize the overspeed relay whereupon motor 62 will be energized to adjust the eccentric 5| as will be more fully explained.

In one installation of our transmission for driving an A. C. generator from an aircraft engine. the device operates as follows:

-position to the impeller |0I.

The low speed cruising R. P. M. of the engine is approximately 1600, the high speed cruising R. P. M. approximately 3.000. and the maximum speed 4,000 R. P. M. The generator speed for normalfrequency output is 8,000 R. P. M. and it is desired to maintain the frequency constant within plus or minus 5% throughout this engine speed range. A 5 to l maximum step-up in the gearing is provided, part of the speed multiplying gear train preferably being disposed in the engine block (not shown) between the engine crankshaft and the input shaft I0.

When the main driving engine is started the eccentric 52 is in underspeed position, as shown in the drawings. and it remains in this position until the engine reaches 1600 R. P. M. at which speed the switch 0| will open under control of the weights 95. When the eccentric is in its extreme underspeed position the limit switch 19 is open so that the underspeed relay 15 does not remain energized.

As the main engine speed advances the switch 0| closes to energize the overspeed relay 15 and the motor 02 is energized through the switch 14 thus rotating the eccentric 52 to.decrease the\ Atricity of the member 52 is then zero and the transmission is running at 1 to l ratio, the input shaft I 0- being driven at twice engine speed (by means of gearing in the engine block, not shown). During normal high speed cruising at an engine speed of 3,000 R. P. M. the eccentric 52 lwill bccupy an intermediate position and the switch 0| is operative to energize the motor 62 through the relay switches for rotation in either direction to maintain a constant speed at the output shaft II.

Our transmission may be made a compact and self -contained unit by mounting the control relays 15, 10 on the casing in connection with the motor 52. It is, therefore. a simple matter of installation to insert the casing I2 between the generator driving member of the main driw'ng engine and the generator to provide a constant speed drive.

In cases where extreme smoothness is desired at the output shaft II, we incorporate a fluid coupling in the drive between the transmission and the generator for damping the oscillations of the shoes 41. Fig. 12 is a sectional elevation of a complete power unit adapted to deliver constant frequency A, C. power when driven from a variablespeed source. l

, In this modillcation of the invention the output shaft |-I of the constant speed transmission is received by the internally .splined hub |00 of an impeller |0| which constitutes the driving element of a fluid couplingv |02. The coupling is encased in a housing |03 having air circulating openings |04. The housing |03 is secured to the housing I2 by bolts |05 and is adapted to support the housing |05 of the alternator |01 to which it is secured by bolts |08.

The iluid coupling |02 is of the kinetic type and includes a driven runner |09 disposed in juxta- Th'e latter has a marginal ilange ||0 forming a shoulder to which is welded a shroud III. This shroud encloses the runner and forms the housing of the coupling. A fluid tight seal ||2 of the bellows type is disposed between the shroud and the hub Ill of the runner for preventing escape of fluid while permitting free rotation of the runner with respect to the impeller.

Th'e runner hub ||2 is internally splined and receives the splined end of the alternator shaft H4. The latter is rotatably supported in the front wall of the casing by a. bearing ||5 and in the cover ||1 by a bearing H0. The cover ||1 is removably secured to the casing |06 by cap `screws ||8 and carries an air duct Il! and a cable duct for accommodating the electrical connections.

The shaft IM carries the alternator rotor |2|. the stator |22 being suitably mounted in th'e housing |06. Slip rings |23 and brushes |24 are provided for electrically connecting the rotor windings to exteriorly located apparatus. Inasmuch as the details of the alternator are not important with respect to the instant invention only enough of the machine is illustrated to make the description complete for present purposes, it being understood that any desired design of alternator (or D, C. generator) may be utilized with our improved transmission depending upon power demands. r

The Fig. 12 power unit is an exceedingly versatile, compact, self-contained power unit which may be assembled in complete form and shipped for assembly with a prime mover, the latter operation requiring only the tightening of the studs i4 and the electrical and lubricant connections. The fluid coupling |02 is filled with fluid to approximately 80% of its capacity through the filler openings |23A at th'e time of assembly and` provides a smooth slip drive between the constant speed gearbox and the alternator.

lSerial No. 432,938, filed on March 2, 1942.

Fig. 13 illustrates a modification of the Fig. l2 arrangement which' has advantages for some uses. In Fig. 13, the fluid coupling |02 is disposed rearwardly of the alternator |01, this arrangement placing the relatively heavy mass ot the alternator closer to the transmission gearbox thus shifting the center of gravity forwardly and in addition permitting the location of the governor mechanism 0| at th'e outer end 0f the assembly where it is more accessible for adjustment.

In this modification, the coupling housing |03' and the alternator housing |00 are of slightly different shape as shown and the air circulating openings are indicated at |20 and |20, communicap screws |29 and splined at 20 to the alternator shaft IH' which is hollow for the accommodation of shaft |21. With this arrangement two fluid seals are required. one designated III, between the impeller hub |20 and the shroud I', and the other designated |32, between the impeller hub and the casing |03'.

The speed-responsive governor switch mechanism 8| is h'oused in a casing |33 at the extreme rear end of the unit where it is readily accessible for adjustment. lThe governor drive shaft 00 has a key-and-slot driving connection with the shaft |21 which permits sliding of the shaft Il' to operate the switch as will be understood.

The operation of the constant speed transmission in the Figs. l2 and 13 arrangements is identical with that previously set forth except that there is always some slip between the alternator shaft and the output shaft because of the fluid coupling. This slip may be compensated for by proper adjustment of the speed responsive switch Il if necessary. The amount f slip is small, on the order of one to two percent at operating speeds and provides a shock absorbing drive which effectively cushions and absorbs the impulses of the crank elements 20 and minimizes the hunting eil'ect of the speed control mechanism.

While we have described only a few of the many possible embodiments of our invention, it is to be understood that these are for illustrative purposes only and areV not to be construed as limiting,the scope of our invention being set forth in the claim appended below.

We claim:

In combination, a rotatable driving carrier, a driven shaft coaxial with the carrier, a driven gear fixed to the driven member adjacent the carrier, an overspeed member mounted on the carrier for angular movement about an axis revolving about the axis of the driving member, an intermediate gear mounted on the overspeed member inspac'ed relation to the carrier, a one-way clutch acting between the overspeed member and the intermediate gear, a first compound gear rotatably mounted on the driven shaft and having two A sections, one section meshing with the intermediate gear, a second compound gear rotatably mounted on the overspeed member between the intermediate gear and the carrier and having two sections, one section meshing with the driven gear and the other section meshing with the other section of the first compound gear, means forming a circular track, control means for the overspeed member traveling on the circular track, and means for making the circular track concentric or eccentric with the axis of the driving carrier and the driven shaft, whereby a concentric posication between the two housings being by way of i tion of the circular track will prevent relative angular movement between the overspeed member and the driving carrier and thereby produce equal angular velocity of the driving carrier andv the driven shaft, and an eccentric position of the circular track will cause rotation of the driving member to produce relative angular movement between the overspeed member and the carrier, said relative angular movement being transmitted through the one-way clutch and the intermediate compound, and driven gears to the driven shaft so as to result in an angular speed of the driven shaft in excess of that of the driving carrie- DELBERT L. Lo'rrs.

HAROLD E. WALDRON. ROY T. BUCY. (References on following me) REFERENCES CITED The following references are of record in thev fileof thispatnt:

UNITED STATES PATENTS Number Number 1p Number Name Date Havill Feb. 27, 1934 Timmermann Aug. 9, 1938 Vespoli July 2, 1940 Obermoser July 30, 1940 Brooks Jan, 13, 1942 Bousman Feb. 9, 1943 FOREIGN PATENTS Country Date France Mar. 17, 1925 (Addition to No. 519.496) :Great Britain Feb. 23, 1928 Great Britain July 26, 1938 France Mar. 26, 1926 Germany Mar. 14, 1939 

